In the field of integrated optics, conventional linear tapers are used for various purposes, such as adiabatic mode-size conversion, edge coupling, and mode conversion. For example, linear bi-layer tapers configured as TM0-TE1 mode converters are described in D. Dai and J. E. Bowers, Opt. Express 19, 10940 (2011), and in W. D. Sacher, T. Barwicz, B. J. F. Taylor, and J. K. S. Poon, Opt. Express 22, 3777 (2014), each of which is hereby incorporated by reference herein in its entirety. On the other hand, when waveguide bending is desired, single-mode waveguide bends are conventionally used to avoid multimode mixing.
There is a need for improved tapers for use in optical waveguide components, for example, with lower loss, lower back-reflection, higher optical bandwidth, and/or other improvements.